No one will know, as a lot of information is missing, we would need to help you.
Minimum PC specifications met?
If Windows, are there other system problems to be solved? Topic: maintenance center
Installation was successful, without warnings?
Is any anti-virus software installed and probably interfering?
Try to create a new user and try there.
If Windows: switch off any non-Windows background software temporarily and try again. If it works then, enable them again step by step to find the culprit.